An electro-hydraulic machine is understood here as a machine which has a pump unit, a drive unit and an associated control unit, designated as a “power pack” for short and in the following as “motor-pump unit (MPU)”. In an MPU, various hydraulic pump types can be used for the pump unit and different electric motors for the drive unit. An MPU is primarily intended for converting electric energy into hydraulic energy. Fields of application for MPUs are, for example, modern electric automobiles, mobile work machines and the industrial sector in general. MPUs can also be operated in a generator operation, depending on the electric motor used, so that hydraulic energy from the hydraulic circuit can be converted into electric energy, i.e., MPUs allowing to be operated both in a motor operation as well as in a generator operation are also known.
For example, in applications in the automotive field, the pressure in hydraulic high-pressure systems has hitherto typically been generated by a hydraulic pump coupled to the combustion engine. This is not possible with hybrid or electric vehicles, because a combustion engine is either not constantly running or is not present. In the future, hydraulic pressures will hence be generated by independent electro-hydraulic units, as is an MPU. With MPUs allowing to be operated also in a generator operation energy from the hydraulic circuit can be fed back into the vehicle electric system as electric energy. Especially in the automotive field, MPUs have to meet particular requirements, such as e.g. a very compact, space- and weight-saving construction, high efficiency, long service life under continuous operation, integrated construction, freedom from maintenance and the like.
For example, DE 102 54 670 A1 shows a compact arrangement between motor and pump housing. DE 10 2014 103 959 A1 and DE 10 2014 103 958 A1 respectively describe a motor-pump unit for the usage in chassis systems of motor vehicles, with the motor and the pump being integrated compactly in each other.
The pressure prevailing in the hydraulic system can be captured via a pressure sensor and be reported as an actual state variable to the electronic control unit of the MPU for further use. For pressure capturing there is usually provided a pressure sensor normally in a valve block or an adaptor piece within the hydraulic line network. For supplying the pressure sensor with electric power and for transmitting a pressure measurement signal to the electronic drive unit, the pressure sensor is usually electrically connected via an electrical cabling or a cable harness with the electronic drive unit.
In applications in the exterior region of the vehicle, e.g. in the underbody portion, the pressure sensors and their mechanical and electrical incorporation must be protected from corrosion and against mechanical influences such as for example stone impact.